Method of testing refrigerating apparatus



' March 16, 1943. H. M. ELSEY METHOD OF TESTING REFRIGERATING APPARATUS Filed May 2. 1940 BY m ATTORNEY WITNESSES:

Patented Mar. 16, 1943 METHOD OF TESTING REFRIGERATING APPARATUS Howard M. Elsey, Oakmont, 1 3 assignor to Westinghouse Electric & Manufacturing -C(mipa'ny, East Pittsburgh, Pa a corporation of Pennsylvania Application May 2, 1940, Serial No. 332,876

4 Claims.

This invention relates to a method for determining the moisture content of containers and more especially for determining the quantity of moisture remaining in the interior of mechanical refrigerating apparatus after the commercial dehydrating process has been completed.

The interiors of mechanical refrigerating apparatus are carefully dehydrated prior to the introduction of the refrigerant but may still contain traces of moisture, oil, cleaning fluids and also refrigerant. The presence of small quanti- V the accompanying drawing, forming a part of,

this application, in which:

Fig. 1 is a schematic drawing showing the moisture-determining apparatus of this invention attached to a refrigerating apparatus; and,

Fig. 2 is a View of the moisture trap of the apparatus.

Referring particularly to the drawing for a detailed description of the invention, the reference numeral 8 designates a vacuum pump driven by an electric motor 9. The vacuum pump 8 is connected by a rubber suction tube it, a portion of a Y connection I I, and a second rubber suction tube l2 with the outlet tube ii) of a moisture trap l3.

The moisture trap I3 is made of tough glass and comprises a transparent cylinder id. The bottom of the cylinder is reduced in diameter to form a long, narrow pocket l5 which is provided with graduations l6 reading in milligrams by means of which the quantity of liquid in the pocket It: may be determined. The upper portion of the glass cylinder connects with an inlet tube I1, and the lower portion with the outlet tube I8 which extends upwardly through the upper wall of the cylinder. All of the interior surfaces of the cylinder l4 and of the inlet and outlet are shaped to drain into the pocket I5. The inlet tube ll of the moisture trap [3 con-- nects through a rubber suction tube It with the refrigerating apparatus 2| to be tested.

. The refrigerating apparatus 2! as shown in Fig. 1 is of conventional design such as commonly used in domestic refrigerators and comprises a compressor-22 driven by an electric'motor23. The motor" 23 and compressor 22 are enclosed in' a hermetically-sealed casing 24. A tube 26 connects the discharge port. of the'compressor 2-2 with a condenser 21. The condenser 21 is connected to an evaporator 29 by a tube 28 having an expansion device 30 therein. A tion tube 3| connects the evaporator 29 with the interior of the sealed casing 24'. A manometer 32 comprising mercury columns 33 i's connected by'a suction tube ttto one leg of @the Y connection M. This manometer v32 measures the degree of suction attained by the vacuum pump 8'.

'The moisture-determining test is conducted as follows. When the'routine dehydrating processofthe refrigerating apparatus is completed, one unit is selected for test purposes. The test is preferably conducted while the unit 2! is still in the dehydrating oven (not shown) which is maintained at a temperature of about 250 F. The tube I9 is connected to the apparatus preferably adjacent the motor 23 because the insulating material of the motor 23, which is formed, for example, of cellulose, is the most difiicult material in the apparatus to dehydrate. The moisture trap l3 and the tube l9 must be carefully dehydrated prior to use, preferably by heating or by rinsing with acetone and thereafter blowing dry air through their interiors. The outlet tube i8 is connected to the vacuum pump 8.

The moisture trap is thereupon immersed in a low temperature solution 36 in a vacuum bottle 3]. A suitable solution for this purpose is a mixture of solid carbon dioxide and dichlorodifiuoromethane. The vacuum pump 8 is now started and maintains a vacuum of one millimeter of mercury or less. The moisture, oil, cleaning fluids, refrigerant, and other liquids which may be in the refrigerating apparatus vaporize and condense on the walls of the moisture trap l3.

After the vacuum has been maintained for about twenty-five minutes the tubes l9 and I2 are removed from the moisture trap I3, and the entrance tube H and the outlet tube it thereof are closed with plugs. The moisture trap is then placed in a centrifuge and whirled to force all of the condensed liquid adhering to the interior surface of the walls of the moisture trap I3 into the pocket I5. The centrifugal forces set up in the liquid in the pocket I5 also prevent the formation of emulsions between the oily and the watery constituents of its contents. The watery constituents will be at the bottom of the pocket [5 and the oily constituents will be arranged in a stratum above. Each stratum may be measured by means of the graduations l6 and the constituents of the strata may later be identified, if necessary, by chemical or physical tests.

It will be apparent from the above that this invention provides an accurate method and apparatus for determining the moisture content of containers and more especially of refrigerating apparatus. It will be further apparent that this method determines the moisture content of such containers and apparatus in the presence of other liquids such as ordinarily are found in refrigerating apparatus.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such liimtations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

l. The method of determining the residual liquid content of a substantially dehydrated receptacle by utilizing a, container embodying a portion of small diameter forming a measuring device, said method comprising chilling said container, evacuating said receptacle, drawing the evacuated vapors and gases through the chilled container to condense said vapors, and then centrifuging said container to force the condensate adhering to the interior surfaces thereof into said measuring device.

2. The method of determining the residual liquid content of a substantially dehydrated receptacle by utilizing a container embodying a portion of small diameter, said method comprising chilling said container, simultaneously heating and evacuating said receptacle, drawing the evacuated vapors and gases through the chilled container to condense said vapors, and then centrifuging said container to force the condensate adhering to the interior surfaces thereof into said portion of small diameter.

3. The method of determining the residual oil-like and water-like content of a substantially dehydrated receptacle by utilizing a trap having a long narrow pocket provided with means for indicating the volume of the liquid therein, which method comprises heating said receptacle while drawing the gases and vapors therein through the trap by evacuation, chilling said trap to condense said vapors, thereafter centrifuging'said trap to force the condensate adhering to the interior wall surfaces thereof into said pocket and to separate the condensate forced into said pocket into its oil-like and waterlike constituents, and thereupon comparing the upper level of at least one of the constituents of said condensate with the indicating means on said pocket to determine the volume of said one constituent.

4. The method of determining the amounts of liquid and condensable vapors in a receptacle, said method comprising heating said receptacle and its contents, withdrawing through a closed conduit comprising a chilled vapor trap substantially all of the vapors and gases in said vessel while the vessel and its contents are hot without permitting said vapors and gases to be replaced by fluids from the exterior of said receptacle, and thereafter centrifuging the vapor trap to consolidate the liquids therein.

HOWARD M. ELSEY. 

